Note 13 - Fair Value - Schedule of Fair Value Assets and Liabilities Measured on Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024
Mortgage-backed securities, at fair value (includes pledged assets of $6,692,991 and $5,209,068, respectively)	$ 6,738,094	$ 5,253,310
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Interest Rate Swap [Member]
Derivative assets, at fair value	0	0
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | TBA Contracts [Member]
Derivative assets, at fair value	0	0
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | Collateralized Mortgage-Backed Securities [Member]
Mortgage-backed securities, at fair value (includes pledged assets of $6,692,991 and $5,209,068, respectively)	0	0
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member] | US Treasury Securities [Member]
Mortgage-backed securities, at fair value (includes pledged assets of $6,692,991 and $5,209,068, respectively)	125,543
Derivative asset, fair value		100,551
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Interest Rate Swap [Member]
Derivative assets, at fair value	6,267	4,574
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | TBA Contracts [Member]
Derivative assets, at fair value	443	4,371
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | Collateralized Mortgage-Backed Securities [Member]
Mortgage-backed securities, at fair value (includes pledged assets of $6,692,991 and $5,209,068, respectively)	6,738,094	5,253,310
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member] | US Treasury Securities [Member]
Mortgage-backed securities, at fair value (includes pledged assets of $6,692,991 and $5,209,068, respectively)	0
Derivative asset, fair value		0
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Interest Rate Swap [Member]
Derivative assets, at fair value	0	0
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | TBA Contracts [Member]
Derivative assets, at fair value	0	0
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | Collateralized Mortgage-Backed Securities [Member]
Mortgage-backed securities, at fair value (includes pledged assets of $6,692,991 and $5,209,068, respectively)	0	0
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member] | US Treasury Securities [Member]
Mortgage-backed securities, at fair value (includes pledged assets of $6,692,991 and $5,209,068, respectively)	$ 0
Derivative asset, fair value		$ 0